This invention relates to a method and apparatus for removing moisture contained in a veneer, and more particularly to a method and apparatus for mechanically removing moisture existing in annular tissues of the wood structure (mostly in the vessels and tracheids) of a veneer.
Heretofore, various attempts have been made in order to remove the moisture of a veneer mechanically instead of by vapor drying. One such attempt is disclosed in Japanese Patent Application Early Publication No. 48(1973)-49905 in the name of the present applicant. However, all of the known art suggest to squeezing out the moisture by means of compressing and deforming the veneer. Although they have such advantages as to use only an extremely small energy and short period of time for removing the moisture compared with the vapor drying by means of a dryer, there are such disadvantages as that the veneer is deformed plastically and broken by means of such compressive deformation. That is, in order to increase the amount of removed moisture, it is simultaneously required to increase the ratio of compressive deformation with respect to the veneer. It eventually causes an overload to the wood structure and results in extensive deterioration of the quality of the plywood as a final product. Because of the foregoing, practically, the ratio of the deformation is obliged to be limited and a satisfactory amount of moisture removal is unavailable.
As a result of extensive and intensive research, the inventor has obtained the knowledge that a veneer sheet contains vessels extending therein slantwise along both surfaces thereof. Said vessels have their respective openings in both surfaces.